Instruction Map

A project log for Kobold K2 - RISC TTL Computer

A 16 bit RISC computer with video display, from just a few TTL and memory chips.

roelhroelh 11/19/2019 at 16:170 Comments

After making many changes, it seems that the instruction set is now finally stable. The instruction set is now very orthogonal. An instruction map was made, that clearly shows the meaning of the upper 8 bits of the instruction (Click on it for a readable version. Excel file is in the file section).

There are four addressing modes:

Almost all instructions write the result to one of the four 16-bit data registers, or one of the four address registers (this includes the PC).

The most used instructions have a color in the map, from top to bottom:

There are several empty positions in the map, so there is room for an extended version that has more instructions.